Natural　layered　aluminosilicate　pyrophyllite　Al-2[Si4O10](OH)(2)　has　been　used　as　a　starting　material　for　preparing　Nasicon-type　fast　ion　conductors　in　the　Na1+3xAlxHf2-xSi2xP3-2xO12　system.　Most　of　the　synthesis　reactions　were　performed　at　900-1150　degrees　C　and　with　increasing　value　of　x,　lower　reaction　temperatures　were　used.　A　single:　NASICON　phase　with　a　C-2/c　space　group　has　been　found　in　the　composition　range　x　less　than　or　equal　to　0.6.　The　volume　of　the-unit-cell　in　this　composition　range　increased　with　increasing　x.　The　initial　composition　with　x　=　0.6　possesses　maximum　ionic　conductivity　which　reaches　values　up　to　1.22　x　10(-2)　S　.　cm(-1)　at　350　degrees　C,　with　an　activation　energy　of　26.3　KJ/mole.